Substrate processing apparatus and method

Abstract

Substrate processing methods and apparatus are disclosed. In some embodiments a substrate processing apparatus may comprise a support structure and a moveable stage including first and second stages. The moveable stage has one or more maglev units attached to the first stage and/or second stage proximate an edge of the first stage. The first stage retains one or more substrates and moves with respect to a first axis that is substantially fixed with respect to the second stage. The second stage translates along a second axis with respect to the support structure. In other embodiments, a primary motor may maintain a rotary stage at an angular speed and/or accelerate or decelerate the stage from a first angular speed to a second angular speed. A secondary motor may accelerate the stage from rest to the first angular speed and/or decelerate the stage from a non-zero angular speed.

1. A substrate processing apparatus, comprising:
 a carrier stage; 
 a rotary stage adapted to retain one or more substrates, wherein the rotary stage is adapted to rotate with respect to the carrier stage about a rotation axis having a substantially fixed position and orientation with respect to the stage; 
 a primary motor adapted to maintain the rotary stage at a desired angular speed and/or rotationally accelerate or decelerate the rotary stage from a first angular speed to a second angular speed; and 
 a secondary motor adapted to rotationally accelerate the rotary stage from rest to the first angular speed and/or rotationally decelerate the rotary stage from a non-zero angular speed to a stop. 
 
     
     
       2. The apparatus of  claim 1  wherein the primary motor is an electric motor having a stator attached to the stage and a rotor attached to the rotary stage. 
     
     
       3. The apparatus of  claim 2  wherein the secondary motor is an electric motor having a stator attached to the stage; a rotor and an engagement mechanism configured to selectively engage the rotor of the secondary motor to the rotary stage or the rotor of the primary motor. 
     
     
       4. The apparatus of  claim 3  wherein the engagement mechanism includes a friction drive. 
     
     
       5. The apparatus of  claim 4  wherein the friction drive is configured to engage the rotary stage proximate a rim thereof. 
     
     
       6. The apparatus of  claim 3  wherein the engagement mechanism includes a clutch plate attached to a shaft of the secondary motor, wherein the clutch plate and a rotor of the primary motor are configured for selective mechanical engagement with each other. 
     
     
       7. The apparatus of  claim 6  wherein the engagement mechanism includes a first facing surface on the clutch plate and a second facing surface on the rotor of the primary rotor. 
     
     
       8. The apparatus of  claim 7  wherein the engagement mechanism is configured to impart relative axial movement between the clutch plate and to the rotor of the primary motor to engage the first and second facing surfaces. 
     
     
       9. The apparatus of  claim 7  wherein one of the first and second facing surfaces includes protrusions and wherein the other of the first and second facing surfaces includes corresponding recesses. 
     
     
       10. The apparatus of  claim 7  wherein the primary and secondary motors are configured to angularly align the first and second facing surfaces with respect to each other to engage the protrusions and the recesses. 
     
     
       11. The apparatus of  claim 2  wherein the primary motor and the secondary motor are configured to rotate about the rotation axis. 
     
     
       12. The apparatus of  claim 11  wherein the rotor of the secondary motor includes a conductive ring attached to the rotary stage, wherein the conductive ring is concentric with the rotation axis and wherein the stator of the secondary motor is configured to produce a rotating magnetic flux that induces eddy currents in the conductive ring, wherein interaction between the eddy currents and the rotating flux exerts a torque on the conductive ring. 
     
     
       13. The apparatus of  claim 12  wherein the stator of the secondary motor includes multiple windings that are built into the carrier stage and the conductive ring is attached to the rotating stage. 
     
     
       14. The apparatus of  claim 13  wherein the stator includes one or more windings oriented such that the flux produced by the windings is oriented radially inward toward the conductive ring. 
     
     
       15. The apparatus of  claim 14  wherein the stator includes one or more windings oriented such that the flux produced by the windings is oriented axially inward toward the conductive ring. 
     
     
       16. The apparatus of  claim 12  wherein the stator of the secondary motor includes one or more sets of three-phase windings with each winding in each set being 120 degrees apart from another winding in that set. 
     
     
       17. The apparatus of  claim 16  wherein the one or more sets of three-phase windings include 6 sets of three-phase windings. 
     
     
       18. The apparatus of  claim 12 , further comprising a center magnetic levitation (maglev) assembly having one or more windings attached to the carrier stage and one or more permanent magnets attached to the rotary stage configured to provide vertical lift force supporting the weight of the rotary stage. 
     
     
       19. The apparatus of  claim 18 , further comprising one or more secondary vertical maglevs having windings attached to the carrier stage proximate a ferromagnetic ring attached to the rotating stage wherein the one or more peripheral vertical maglevs are configured to provide forces for stabilizing the rotary stage in a plane of rotation. 
     
     
       20. The apparatus of  claim 19  wherein the secondary maglevs and ferromagnetic ring are located proximate a periphery of the rotary stage. 
     
     
       21. The apparatus of  claim 19  wherein the secondary maglevs and ferromagnetic ring are located proximate an axis of rotation of the rotary stage. 
     
     
       22. The apparatus of  claim 19 , further comprising one or more radial maglevs configured to provide radial forces for centering the rotation of the stage about its axis. 
     
     
       23. The apparatus of  claim 22  wherein the radial maglevs include one or more windings attached to the carrier stage and a ferromagnetic ring attached to the rotary stage. 
     
     
       24. The apparatus of  claim 1  wherein the primary motor is characterized by a relatively low torque ripple and the secondary motor is characterized by a relatively high torque ripple compared to the primary motor. 
     
     
       25. The apparatus of  claim 1 , further comprising a support structure, wherein the carrier stage is a linear translation stage adapted to translate with respect to the support structure along a translation axis, whereby the rotary stage translates with respect to the support structure along with the linear translation stage. 
     
     
       26. The apparatus of  claim 25  wherein the wherein the primary motor is an electric motor having a stator attached to the carrier stage and a rotor attached to the rotary stage. 
     
     
       27. The apparatus of  claim 26  wherein the rotor and stator are configured such that magnetic forces exerted by the stator on the rotor are sufficient to support all or most of the weight of the rotary stage. 
     
     
       28. The apparatus of  claim 26  wherein the secondary motor is attached to the support structure, the apparatus further comprising an engagement mechanism configured to selectively engage the secondary motor to the rotary stage or the rotor of the primary motor. 
     
     
       29. The apparatus of  claim 28  wherein the engagement mechanism includes a magnetic clutch. 
     
     
       30. The apparatus of  claim 25  wherein the support structure is stage base that supports the carrier stage or a lid of a chamber that contains the carrier stage and the rotary stage. 
     
     
       31. The apparatus of  claim 25 , further comprising one or more magnetic levitation (maglev) units attached to the rotary stage and/or translation stage proximate an edge of the rotary stage. 
     
     
       32. The apparatus of  claim 1  further comprising one or more sensors adapted to sense changes in position of the rotary stage and/or carrier stage and/or a substrate processing tool with respect to a metrology reference frame. 
     
     
       33. The apparatus of  claim 32  wherein the metrology reference frame is fixed with respect to a base that supports the carrier stage and rotary stage or a chamber that contains the carrier stage and rotary stage. 
     
     
       34. The apparatus of  claim 32  wherein one or more sensors include one or more differential interferometers. 
     
     
       35. A substrate processing apparatus, comprising:
 a support structure; 
 a rotary-linear stage having a rotating stage and a linear translation stage, wherein the rotary stage is adapted to retain a plurality of substrates, wherein the rotary stage is adapted to rotate in a continuous motion about a rotation axis having a substantially fixed position and orientation with respect to the linear translation stage, and wherein the linear translation stage is adapted to translate with respect to the support structure along a translation axis; 
 a primary motor adapted to maintain the rotary stage at a desired angular speed and/or accelerate or decelerate the rotary stage from a first angular speed to a second angular speed; 
 a secondary motor adapted to accelerate the rotary stage from rest to the first angular speed and/or decelerate the rotary stage from a non-zero angular speed to a stop; and 
 a lithography, inspection or metrology tool in a substantially fixed position with respect to the support structure. 
 
     
     
       36. The apparatus of  claim 35  wherein the lithography, inspection or metrology tool includes an electron beam column, optical column or x-ray column. 
     
     
       37. The apparatus of  claim 35 , further comprising a control system adapted to control a position of the substrates relative to the tool to within 40 nanometers of a desired position. 
     
     
       38. The apparatus of  claim 35  wherein the primary motor is an electric motor having a stator attached to the carrier stage and a rotor attached to the rotary stage. 
     
     
       39. The apparatus of  claim 38  wherein the rotor and stator are configured such that magnetic forces exerted by the stator on the rotor are sufficient to support all or most of the weight of the rotary stage. 
     
     
       40. The apparatus of  claim 38  wherein the secondary motor is an electric motor having a stator attached to the carrier stage; and a rotor and an engagement mechanism configured to selectively engage the rotor of the secondary motor to the rotary stage or the rotor of the primary motor. 
     
     
       41. The apparatus of  claim 40  wherein the engagement mechanism includes a friction drive. 
     
     
       42. The apparatus of  claim 41  wherein the friction drive is configured to engage the rotary stage proximate a rim thereof. 
     
     
       43. The apparatus of  claim 42  wherein the engagement mechanism includes a clutch plate attached to a shaft of the secondary motor, wherein the clutch plate and a rotor of the primary motor are configured for selective mechanical engagement with each other. 
     
     
       44. The apparatus of  claim 43  wherein the engagement mechanism includes a first facing surface on the clutch plate and a second facing surface on the rotor of the primary rotor. 
     
     
       45. The apparatus of  claim 44  wherein the engagement mechanism is configured to impart relative axial movement between the clutch plate and to the rotor of the primary motor to engage the first and second facing surfaces. 
     
     
       46. The apparatus of  claim 44  wherein one of the first and second facing surfaces includes protrusions and wherein the other of the first and second facing surfaces includes corresponding recesses. 
     
     
       47. The apparatus of  claim 44  wherein the primary and secondary motors are configured to angularly align the first and second facing surfaces with respect to each other to engage the protrusions and the recesses. 
     
     
       48. The apparatus of  claim 35  wherein the primary motor and the secondary motor are configured to rotate about the rotation axis. 
     
     
       49. The apparatus of  claim 48  wherein the rotor of the secondary motor includes a conductive ring attached to the rotary stage, wherein the conductive ring is concentric with the rotation axis and wherein the stator of the secondary motor is configured to produce a rotating magnetic flux that induces eddy currents in the conductive ring, wherein interaction between the eddy currents and the rotating flux exerts a torque the conductive ring. 
     
     
       50. The apparatus of  claim 49  wherein the primary motor is characterized by a relatively low torque ripple and the secondary motor is characterized by a relatively high torque compared to the primary motor. 
     
     
       51. The apparatus of  claim 35  wherein the carrier stage is a linear translation stage adapted to translate with respect to the support structure along a translation axis, whereby the rotary stage translates with respect to the support structure along with the linear translation stage. 
     
     
       52. The apparatus of  claim 51  wherein the wherein the primary motor is an electric motor having a stator attached to the carrier stage and a rotor attached to the rotary stage. 
     
     
       53. The apparatus of  claim 52  wherein the rotor and stator are configured such that magnetic forces exerted by the stator on the rotor are sufficient to support all or most of the weight of the rotary stage. 
     
     
       54. The apparatus of  claim 52  wherein the secondary motor is attached to the support structure, the apparatus further comprising an engagement mechanism configured to selectively engage the secondary motor to the rotary stage or the rotor of the primary motor. 
     
     
       55. The apparatus of  claim 54  wherein the engagement mechanism includes a magnetic clutch. 
     
     
       56. The apparatus of  claim 35  wherein the support structure is a base that supports the carrier stage or a chamber that contains the carrier stage and the rotary stage. 
     
     
       57. The apparatus of  claim 35  further comprising one or more magnetic levitation (maglev) units attached to the rotary stage and/or translation stage proximate an edge of the rotary stage. 
     
     
       58. A method for processing a substrate, comprising:
 retaining a plurality of substrates on a rotary stage, 
 rotationally accelerating the rotary stage relative to a carrier stage from rest to a first angular speed and/or decelerating the rotary stage from a non-zero angular speed to a stop using a booster motor; 
 maintaining the rotary stage at a desired angular speed and/or rotationally accelerating or decelerating the rotary stage from a first angular speed to a second angular speed using a primary motor characterized by a relatively low torque ripple; and 
 translating the linear translation stage with respect to a support structure along a translation axis while processing the substrates with a lithography, inspection or metrology tool that is in a substantially fixed position with respect to the support structure. 
 
     
     
       59. The method of  claim 58 , further comprising controlling a position of the substrates relative to the tool to within 40 nanometers of a desired position. 
     
     
       60. The method of  claim 59  wherein controlling the position of the substrate relative to the tool includes supporting a weight of the rotary stage using a central rotor attached to the rotary stage and a stator attached to the linear translation stage. 
     
     
       61. The method of  claim 60  wherein supporting the weight of the rotary stage includes using magnetic forces between the rotor and the stator to support all or most of the weight of the rotary stage. 
     
     
       62. The method of  claim 58 , further comprising selectively engaging and disengaging the booster motor from the rotary stage. 
     
     
       63. The method of  claim 62  wherein selectively engaging and disengaging the booster motor includes rotating a rotor of the booster motor and the rotary stage at the same angular speed. 
     
     
       64. The method of  claim 63  wherein selectively engaging and disengaging the booster motor further includes angularly aligning the rotor of the booster motor with respect to the rotary stage. 
     
     
       65. The method of  claim 58  wherein the primary motor is an electric motor having a stator attached to a carrier stage and a rotor attached to the rotary stage. 
     
     
       66. The method of  claim 65  wherein the secondary motor is an electric motor having a stator attached to the linear translation stage. 
     
     
       67. The method of  claim 58  wherein rotationally accelerating the rotary stage from rest to the first angular speed and/or decelerating the rotary stage from a non-zero angular speed to a stop using a booster motor includes applying a driving force to the rotary stage proximate a rim thereof with the booster motor. 
     
     
       68. The method of  claim 58  wherein the primary motor and the secondary motor are configured to rotate about the rotation axis. 
     
     
       69. The method of  claim 58  wherein rotationally accelerating the rotary stage includes applying a rotating magnetic flux to a conductive ring attached to the rotary stage, wherein the conductive ring is concentric with the rotation axis, wherein the rotating magnetic flux induces eddy currents in the conductive ring, wherein interaction between the eddy currents and the rotating flux exerts a torque the conductive ring, thereby rotationally accelerating the rotary stage.